The HST key programme on the distance scale is expected to fix the value of Hubble's constant to an accuracy of about 10 per cent.

The questions in the exam paper itself were a mixture of modern cosmology, such as calculating Hubble's constant from a graph of recent data, and more traditional fare about the various forces acting on the balloon.

Spectral studies requiring dedicated Hubble time would be routine with every one of SNAP's supernova observations.